Articles by John Siegenthaler, P.E.

A designer needs to tie in an indirect water heater to a multiple boiler system. He selects a hydraulic separator for the project and connects the piping of the indirect water heater on the same side as the boilers.

The designer’s intent was to supply a low-temperature floor-heating zone, as well as a higher-temperature baseboard zone and air handler, from a thermal storage tank heated by a pellet-fueled boiler.

An installer sets up a zoned distribution system. To keep it simple, he uses the same size piping for the headers and all the distribution circuits. The heat source is a low-mass copper tube boiler with high flow resistance.

An installer who is used to boiler replacements may view the mechanical room aspects of changing from a boiler to a geothermal heat pump the same as a boiler changeout; just swapping out one “box” for another. Unfortunately, this can lead to some significant operating problems.